JP5449729B2 - Photosensitive resin composition - Google Patents

Description

  The present invention relates to a photosensitive resin composition which is cured by light irradiation and can be alkali-developed.

Photosensitive resin compositions are widely used for various applications. For example, in a printed wiring board, a photosensitive resin composition is widely used as a photo solder resist as a permanent protective film for a circuit.
Photo solder resist is a film formed on the entire surface excluding the part to be soldered of the circuit conductor, and when wiring electronic parts on the printed circuit board, it prevents solder from adhering to unnecessary parts, It is used as a protective coating that prevents the circuit from being directly exposed to air.
Currently, liquid photo solder resists are widely used as photo solder resists for printed wiring boards from the viewpoints of high precision, high density, and environmental problems.

  As this liquid photo solder resist ink, a solder resist ink composition (for example, Patent Document 1) mainly composed of a partial reaction product of a novolak epoxy resin with acrylic acid has been proposed. However, these ink compositions have a problem that alkali developability is insufficient and warpage due to curing shrinkage is large.

On the other hand, a photo solder resist (for example, Patent Document 2) containing a compound having an oxetanyl group and an imidazole compound has been proposed.
However, although it is excellent in alkali developability, the reduction of warpage due to curing shrinkage was insufficient.
As described above, a photo solder resist having excellent alkali developability and extremely low warpage due to curing shrinkage has not yet been obtained.
JP-A-61-59447 JP 2005-105006 A

  An object of the present invention is to provide a photosensitive resin composition that is excellent in alkali developability and extremely small in warpage due to curing shrinkage, and is particularly suitable for a photo solder resist.

As a result of intensive studies to solve the above problems, the inventors of the present invention can obtain a cured product having extremely low warpage due to curing shrinkage as well as excellent alkali developability when a carboxyl group-modified cellulose having an aromatic ring is used. And reached the present invention.
That is, the present invention relates to hydrophilic vinyl resin (A1) or hydrophilic epoxy resin (A2) , polyfunctional (meth) acrylate monomer (B), carboxyl group-modified cellulose (C) having an aromatic ring in the molecule. And an alkali developable photosensitive resin composition (Q) containing a radical photopolymerization initiator (D), wherein the content of the modified cellulose (C) is a solid content of the photosensitive resin composition (Q). The photosensitive resin composition is 3 to 25% by weight based on the weight of the minute, and the acid value of the modified cellulose (C) is 10 to 90 mgKOH / g.

  The photosensitive resin composition of the present invention is excellent in alkali developability and has a very small warp due to curing shrinkage, and provides a photosensitive resin composition that is particularly suitable for a solder resist in a printed wiring board.

  The photosensitive resin composition of the present invention comprises a hydrophilic resin (A), a polyfunctional (meth) acrylate monomer (B), a carboxyl group-modified cellulose (C) having an aromatic ring, and a radical photopolymerization initiator (D). And a cured product that has excellent alkali developability and extremely low warpage due to curing shrinkage.

  In the above and the following, for example, the expression with (meth) such as “(meth) acrylate” means “acrylate and / or methacrylate”.

  Below, (A)-(D) which is an essential structural component of the photosensitive resin composition of this invention is demonstrated in detail in order.

First, in the hydrophilic resin (A), the hydrophilicity index is defined by HLB. Generally, the larger this value, the higher the hydrophilicity.
The preferred range of the HLB value of the hydrophilic resin (A) varies depending on the resin skeleton of the hydrophilic resin (A) (for example, vinyl resin, epoxy resin, polyester resin, etc.), but usually 4 to 19, preferably It is 5-18, More preferably, it is 6-17.
When it is 4 or more, developability is further improved when alkali development is performed, and when it is 19 or less, the water resistance of the cured product is further improved.
In addition, HLB in this invention is an HLB value by the Oda method, is a hydrophilicity-hydrophobicity balance value, and can be calculated from the ratio of the organic value and inorganic value of an organic compound.
HLB≈10 × inorganic / organic In addition, the inorganic value and the organic value are described on page 501 of the document “Synthesis of Surfactant and its Application” (published by Tsuji Shoten, written by Oda, Teramura); It is described in detail on page 198 of “Introduction to New Surfactants” (Takehiko Fujimoto, published by Sanyo Chemical Industries, Ltd.).

  The solubility parameter (hereinafter abbreviated as SP value) of the hydrophilic resin (A) is preferably 7 to 14, more preferably 8 to 13, particularly preferably 10 to 13. When it is 7 or more, the alkali developability is further improved, and when it is 14 or less, the water resistance of the cured product is further improved. Those whose SP values are close to each other are easy to mix with each other (high dispersibility), and those whose numerical values are apart from each other are indicators that are difficult to mix.

  The SP value in the present invention is calculated by the method described in the following document proposed by Fedors et al.

"POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol. 14, No. 2, Robert F. Fedors. (Pp. 147-154)"

The hydrophilic resin (A) preferably has a carboxyl group in the molecule from the viewpoint of alkali developability. The carboxyl group content is indicated by an acid value.
The acid value of the hydrophilic resin (A) is usually 10 to 50 mgKOH / g, preferably 20 to 40 mgKOH / g.
When it is 10 mgKOH / g or more, the alkali developability is more easily exhibited, and when it is 50 mgKOH / g or less, the water resistance of the cured product can be exhibited more favorably.

The acid value in the present invention can be measured by an indicator titration method using an alkaline titration solution.
The method is as follows.
(I) About 1 g of a sample is precisely weighed and placed in an Erlenmeyer flask, and then a neutral methanol / acetone solution (a mixture of acetone and methanol at 1: 1 (volume ratio)) is added and dissolved.
(Ii) Add several drops of phenolphthalein indicator and titrate with 0.1 mol / L potassium hydroxide titration solution. The end point of neutralization is defined as the time when the indicator is slightly red for 30 seconds.
(Iii) Determine using the following equation.
Acid value (mgKOH / g) = (A × f × 5.61) / S
However, A: The number of mL of 0.1 mol / L potassium hydroxide titration solution.
f: Potency of 0.1 mol / L potassium hydroxide titration solution
S: Sampling amount (g)

Examples of the hydrophilic resin (A) include a hydrophilic vinyl resin (A1), a hydrophilic epoxy resin (A2), a hydrophilic polyester resin, a hydrophilic polyamide resin, a hydrophilic polycarbonate resin, and a hydrophilic polyurethane resin. . A hydrophilic resin (A) may be used by 1 type, and may use 2 or more types together.
Among these, the hydrophilic vinyl resin (A1) and the hydrophilic epoxy resin (A2) are preferable from the viewpoint of the hardness of the obtained cured product and the ease of production.

Examples of the hydrophilic vinyl resin (A1) include those having a hydrophilic group in the side chain and / or terminal of the vinyl polymer molecule. Examples of the hydrophilic group include a carboxyl group, a hydroxyl group, a sulfonic acid group, a primary amino group, a secondary amino group, an amide group, a polyether group, and a combination of two or more of these.
In order to exhibit sufficient developability, those having a hydrophilic group, particularly a carboxyl group in the side chain are preferred. The hydrophilic vinyl resin (A1) may contain a (meth) acryloyl group for the purpose of improving curability.

  A preferred method for producing the hydrophilic vinyl resin (A1) includes a vinyl monomer (a) having a hydrophilic group alone, and if necessary, a vinyl monomer (a) having this hydrophilic group and a hydrophobic group having no hydrophilic group. It is obtained by vinyl polymerization in combination with the vinyl monomer (b).

Examples of the vinyl monomer (a) having a hydrophilic group include the following vinyl monomers (a1) to (a8).
(A1) Hydroxyl-containing vinyl monomer:
Hydroxyalkyl (meth) acrylate [2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, etc.], polyalkylene glycol mono (meth) acrylate [polyethylene glycol mono (meta ) Acrylate etc.], alkylol (meth) acrylamide [N-methylol (meth) acrylamide etc.], hydroxystyrene and 2-hydroxyethylpropenyl ether.
Among (a1), preferred is hydroxyalkyl (meth) acrylate, particularly 2-hydroxyethyl (meth) acrylate, from the viewpoint of alkali developability.

(A2) Carboxyl group-containing vinyl monomer:
Unsaturated monocarboxylic acids [such as (meth) acrylic acid, crotonic acid and cinnamic acid], unsaturated polyvalent (2-4 valent) carboxylic acids [such as (anhydrous) maleic acid, itaconic acid, fumaric acid and citraconic acid], Unsaturated polyvalent carboxylic acid alkyl (alkyl group having 1 to 10 carbon atoms) ester [maleic acid monoalkyl ester, fumaric acid monoalkyl ester, citraconic acid monoalkyl ester, etc.] and salts thereof [alkali metal salt (sodium salt) And potassium salts, etc.), alkaline earth metal salts (calcium salts and magnesium salts, etc.), amine salts and ammonium salts, etc.].
Of (a2), preferred is an unsaturated monocarboxylic acid from the viewpoint of hydrophilicity, and more preferred is (meth) acrylic acid.

(A3) Primary or secondary amino group-containing vinyl monomer:
Primary amino group-containing (meth) acrylate [aminoalkyl (meth) acrylate such as aminoethyl (meth) acrylate and aminopropyl (meth) acrylate)] Secondary amino group-containing (meth) acrylate [N-methylaminoethyl (meth) ) Acrylates and monoalkylaminoalkyl (meth) acrylates such as N-methylaminopropyl (meth) acrylate].

(A4) Sulphonic acid group-containing vinyl monomer:
Examples thereof include vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, α-methyl styrene sulfonic acid, 2- (meth) acryloylamido-2-methylpropane sulfonic acid, and salts thereof. Examples of the salt include alkali metal (sodium and potassium) salts, alkaline earth metal (calcium and magnesium) salts, primary to tertiary amine salts, ammonium salts and quaternary ammonium salts.

(A5) Tertiary amino group-containing vinyl monomer:
Tertiary amino group-containing (meth) acrylates [dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate)] and the like.

(A6) Amide group-containing vinyl monomer:
(Meth) acrylamide, N-alkyl (C1-6) (meth) acrylamide, diacetone acrylamide, N, N'-methylene-bis (meth) acrylamide, N, N-dialkyl (C1-6) or Diaralkyl (7 to 15 carbon atoms) (meth) acrylamide (for example, N, N-dimethylacrylamide and N, N-dibenzylacrylamide), methacrylformamide, N-methyl-N-vinylacetamide, cinnamic amide and cyclic amide (N-vinylpyrrolidone, N-allylpyrrolidone, etc.).

(A7) a quaternary ammonium base-containing vinyl monomer;
A quaternized product of a tertiary amino group-containing vinyl monomer having 6 to 50 carbon atoms (preferably 8 to 20 carbon atoms, such as methyl chloride, dimethyl sulfate, benzyl chloride and dimethyl carbonate), for example, dimethyl Examples include quaternized products of aminoethyl (meth) acrylate, quaternized products of diethylaminoethyl (meth) acrylate, quaternized products of dimethylaminoethyl (meth) acrylamide, and quaternized products of diethylaminoethyl (meth) acrylamide.

(A8) Polyether group-containing vinyl monomer:
Alkoxy (alkoxy group having 1 to 8 carbon atoms) polyalkylene (alkylene group having 2 to 4 carbon atoms) glycol mono (meth) acrylate [methoxypolyethylene glycol (degree of polymerization 2 to 40) mono (meth) acrylate and methoxypolypropylene glycol ( Polymerization degree 2-30) mono (meth) acrylate, etc.].

  Among the vinyl monomers (a) having the above hydrophilic groups, (a1) and (a2) are preferable from the viewpoint of exhibiting sufficient developability and crosslinkability, and (a2) is particularly preferable.

  Examples of the hydrophobic group-containing vinyl monomer (b) having no hydrophilic group used in combination with the vinyl monomer (a) having a hydrophilic group include the following nonionic monomers (b1) to (b6).

(B1) (meth) acrylic acid ester;
C1-C20 alkyl (meth) acrylate of an alkyl group [for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, n-hexyl (meth) acrylate and 2-ethylhexyl (meth) acrylate, etc.]; alicyclic group-containing (meth) acrylate [dicyclopentanyl (meth) acrylate, sidiclopentenyl (meth) acrylate, isobornyl (meth) acrylate, etc. ];

(B2) an aromatic hydrocarbon monomer;
And hydrocarbon monomers having a styrene skeleton [for example, styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butylstyrene, phenylstyrene, cyclohexylstyrene, and benzylstyrene] and vinylnaphthalene. It is done.

(B3) carboxylic acid vinyl ester;
Examples thereof include those having 4 to 50 carbon atoms, such as vinyl acetate, vinyl propionate and vinyl butyrate.
(B4) vinyl ether monomers;
Those having 3 to 50 (preferably 6 to 20) carbon atoms such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl butyl ether and the like can be mentioned.
(B5) vinyl ketone monomer;
Examples thereof include those having 4 to 50 carbon atoms, such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl phenyl ketone.
(B6) a halogen atom-containing monomer;
Examples thereof include those having 2 to 50 (preferably 2 to 20) carbon atoms, such as vinyl chloride, vinyl bromide, vinylidene chloride, chlorostyrene and bromostyrene.

  Among (b) having no hydrophilic group, (b1) is preferable from the viewpoint of curability, and alicyclic group-containing (meth) acrylate is more preferable.

  The charged monomer mol% of (a) / (b) in the hydrophilic vinyl resin (A1) is usually 10-100 / 0 to 90, preferably 10 to 90/10 to 90 from the viewpoint of curability and developability. More preferably, it is 20-80 / 20-80.

The hydrophilic vinyl resin (A1) is a polymer having the above (a) and, if necessary, (b) as a constituent monomer, and a (meth) acryloyl group as a side chain for the purpose of further improving curability. You may make it contain.
Examples of the method of incorporating a (meth) acryloyl group in the side chain include the following methods (1) and (2).
(1) Using a monomer [(a1) and / or (a3)] having a group capable of reacting with an isocyanate group (such as a hydroxyl group or a primary or secondary amino group) in at least a part of (a) A method of producing a polymer and then reacting a compound having a (meth) acryloyl group and an isocyanate group (such as acryloylethyl isocyanate);
(2) A method in which a hydrophilic group in a polymer is reacted with a compound (such as glycidyl acrylate) having a (meth) acryloyl group and an epoxy group.

  When the hydrophilic vinyl resin (A1) has a carboxyl group as a hydrophilic group, the content of the carboxyl group in the hydrophilic vinyl resin (A1) may be a certain value or more from the viewpoint of developability and curability. Preferably, from the viewpoint of water resistance of the cured product, the carboxyl group content is preferably not more than a certain value.

The carboxyl group content in the hydrophilic vinyl resin (A1) is indicated by an acid value.
When the acid value of the hydrophilic vinyl resin (A1) is 10 mgKOH / g or more, the developability is more easily exhibited and the resin is easily cured. Moreover, if it is 50 mgKOH / g or less, the water resistance of hardened | cured material can exhibit more favorable.

  Moreover, SP value of hydrophilic vinyl-type resin (A1) becomes like this. Preferably it is 7-14, More preferably, it is 9-13, Most preferably, it is 11-13. When it is 7 or more, the developability can be further improved, and when it is 14 or less, the water resistance of the cured product is further improved.

  The number average molecular weight (hereinafter abbreviated as Mn, measured by gel permeation chromatography) of the hydrophilic vinyl resin (A1) is preferably 500 to 500 from the viewpoint of hardness and developability when it becomes a cured product. 500,000, more preferably 1,000 to 100,000, and particularly preferably 3,000 to 20,000.

The production of the hydrophilic vinyl resin (A1) can be carried out by ordinary radical polymerization.
The radical polymerization is performed, for example, by polymerizing a monomer with a radical polymerization initiator using an organic solvent if necessary.
Organic solvents include glycol ethers (such as ethylene glycol monoalkyl ether and propylene glycol monoalkyl ether), ketones (such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone), and esters (butyl acetate, ethylene glycol alkyl ether acetate). And propylene glycol alkyl ether acetate). Of the organic solvents, ketones and esters are preferred.
When the organic solvent is used, the amount used is not particularly limited, but is usually 1 to 400% by weight, preferably 5 to 300% by weight, particularly preferably 10 to 200% by weight based on the total weight of the monomers.
The organic solvent may be removed by a method such as distillation by heating after completion of the polymerization, but may be left as it is and may be part of the organic solvent that may be contained in the photosensitive resin composition described later.

Examples of the polymerization initiator include peroxides and azo compounds.
Peroxides include inorganic peroxides (eg, hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, etc.) and organic peroxides (eg, benzoyl peroxide, di-t-butyl peroxide, Cumene hydroperoxide, lauryl peroxide, etc.). Examples of the azo compound include azobis (2,4-dimethylvaleronitrile), azobisisobutyronitrile, azobis (2-methylbutyronitrile), azobiscyanovaleric acid and its salts (for example, hydrochloride), and azobis (2 -Amidinopropane) hydrochloride and the like. Preferred is an azo compound. As a usage-amount of a polymerization initiator, 0.0001-20% is preferable normally based on the total weight of a monomer, More preferably, it is 0.001-15%, Most preferably, it is 0.005-10%. The reaction temperature and reaction time are appropriately determined depending on the type of radical polymerization initiator.

The hydrophilic epoxy resin (A2) in the hydrophilic resin (A) in the present invention is a polymer of an epoxy resin skeleton having a hydrophilic group.
As the hydrophilic group contained in the hydrophilic epoxy resin (A2), a carboxyl group, a hydroxyl group, a sulfonic acid group, a primary amino group, and a secondary amino group are the same as those mentioned for the hydrophilic vinyl resin (A1). Amide groups, polyether groups, and combinations of two or more thereof. In order to exhibit sufficient developability, those having a carboxyl group are particularly preferable. ←

A preferred method for producing the hydrophilic epoxy resin (A2) is to react an epoxy group in an ordinary epoxy resin (A2 ₀ ) with, for example, an acryloyl group-containing monocarboxylic acid to open the epoxy group to form a hydroxyl group. A method of reacting a part of the hydroxyl group with a polyvalent carboxylic acid or the polyvalent carboxylic acid anhydride (e) is not limited thereto.

Examples of the epoxy resin (A2 ₀ ) before modification include aliphatic epoxy resins [for example, Epototo YH-300, PG-202, PG-207 (all manufactured by Tohto Kasei Co., Ltd.)] and alicyclic epoxy resins [for example, CY. -179, CY-177, CY-175 (all manufactured by Asahi Kasei Epoxy Co., Ltd.)] and aromatic epoxy resins [eg, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A epoxy resin, biphenyl type epoxy resin and glycidyl Modified polyvinylphenol and the like].
Of the epoxy resins (A2 ₀ ), aromatic epoxy resins are preferable from the viewpoint of curability.

Examples of the acryloyl group-containing monocarboxylic acid for modification include acrylic acid.
In the production of the hydrophilic epoxy resin (A2), the charged weight ratio of acrylic acid / epoxy resin (A2 ₀ ) is preferably such that the concentration of the acryloyl group of the hydrophilic epoxy resin (A2) is 1.0 mmol / g or more. The weight ratio of acrylic acid is such that From the above viewpoint, the weight ratio of acrylic acid / epoxy resin (A2 ₀ ) is preferably 0.072 or more / 1, and more preferably 0.079 to 0.72 / 1.

Although the reaction temperature in reaction of an epoxy resin (A2 ₀ ) and acrylic acid is not specifically limited, Preferably it is 70-110 degreeC. The reaction time is not particularly limited, but is preferably 5 to 30 hours. Further, if necessary, a catalyst (for example, triphenylphosphine) and a radical polymerization inhibitor (hydroquinone, p-methoxyphenol, etc.) may be used.

  Moreover, as polyhydric carboxylic acid and polyhydric carboxylic acid anhydride (e), unsaturated polyhydric carboxylic acid of those vinyl monomers (a) and their anhydrides, and saturated polyhydric (2-6 valent) ) Carboxylic acids (eg, aliphatic saturated polycarboxylic acids such as oxalic acid, succinic acid, phthalic acid, adipic acid, dodecanedioic acid, dodecenyl succinic acid, pentadecenyl succinic acid and octadecenyl succinic acid; tetrahydrophthalic acid , Hexahydrophthalic acid, methyltetrahydrophthalic acid, trimellitic acid, pyromellitic acid, aromatic polycarboxylic acids such as biphenyltetracarboxylic acid and naphthalenetetracarboxylic acid) and their anhydrides (eg, succinic anhydride, dodecenyl) Fats such as succinic anhydride, pentadecenyl succinic anhydride and octadecenyl succinic anhydride Saturated polycarboxylic anhydrides: phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, biphenyltetracarboxylic anhydride and naphthalenetetracarboxylic anhydride Aromatic polyhydric carboxylic acid anhydrides such as products). A saturated polycarboxylic acid anhydride is preferable from the viewpoint of reactivity and developability.

The charging equivalent of (e) with respect to the weight of the acrylic acid adduct of the epoxy resin (A2 ₀ ) is such that the acid value of the hydrophilic epoxy resin (A2) is preferably 10 to 50 mgKOH / g ( e), for example, when (e) is a divalent carboxylic acid or anhydride thereof, the charge equivalent of (e) / the weight of the acrylic acid adduct of the epoxy resin (A2 ₀ ) is From the viewpoint, it is preferably 0.18 to 0.89 meq / g, more preferably 0.53 to 0.71 meq / g.

The reaction temperature in the reaction of (A2 ₀ ) acrylic acid adduct and (e) is not particularly limited, but is preferably 70 to 110 ° C. The reaction time is not particularly limited, but is preferably 3 to 10 hours.

  When the hydrophilic epoxy resin (A2) has a carboxyl group as a hydrophilic group, the content of the carboxyl group in the hydrophilic epoxy resin (A2) may be a certain value or more from the viewpoint of developability and curability. Preferably, from the viewpoint of water resistance of the cured product, the content of the carboxyl group in (A2) is preferably not more than a certain value.

The content of the carboxyl group in the hydrophilic epoxy resin (A2) is indicated by an acid value, and the preferred acid value of the hydrophilic epoxy resin (A2) is 10 to 50 mgKOH / g as in the case of (A1). There is the same reason for preference.
The SP value of the hydrophilic epoxy resin (A2) is preferably 7 to 14, more preferably 9 to 13, and particularly preferably 11 to 13, as in the case of the hydrophilic vinyl resin (A1). . When it is 7 or more, the developability can be further improved, and when it is 14 or less, the water resistance of the cured product is further improved.

  The number average molecular weight (Mn) of the hydrophilic epoxy resin (A2) is usually 500 to 3,000, preferably 1,000 to 2,800, particularly from the viewpoint of hardness and developability when it becomes a cured product. Preferably, it is 1,500 to 2,500.

The hydrophilic resin (A) of the present invention includes two or more hydrophilic vinyl resins (A1), two or more hydrophilic epoxy resins (A2), or a combination of (A1) and (A2). It can be used above.
In this case, the “HLB value of the hydrophilic resin (A)” can be obtained by calculating the arithmetic average of the weight ratios of the HLB values of the various (A) used.
Similarly, “SP value of hydrophilic resin (A)” of the present invention when two or more hydrophilic resins are used in combination is an arithmetic average of the weight ratios of the SP values of various (A) used. By doing so, it can be obtained.

Based on the weight of the solid content of the photosensitive resin composition (Q) of the present invention, the content of the hydrophilic resin (A) is 10 to 80% by weight, preferably 20 to 60% by weight. If it is 10% or more, the developability can be further improved, and if it is 80% or less, the hardness of the cured product is further improved.
The “solid content” in the present invention refers to components other than the solvent.

Subsequently, the polyfunctional (meth) acrylate monomer (B) in the photosensitive resin composition of the present invention will be described in detail.
The polyfunctional (meth) acrylate monomer (B) is not particularly limited as long as it is a known polyfunctional (meth) acrylate monomer, and is used without limitation. Bifunctional (meth) acrylate (B1), trifunctional (meth) acrylate (B2) and 4-6 functional (meth) acrylate (B3) are mentioned.

  Examples of the bifunctional acrylate (B1) include ethylene glycol diacrylate, diethylene glycol diacrylate, propylene glycol diacrylate, dipropylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, glycerin diacrylate, 1 , 4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, 2- Butyl-2-ethyl-1,3-propanediol diacrylate, dimethylol-tricyclodecane diacrylate, ethylene of bisphenol A Diacrylate of xide adduct, diacrylate of propylene oxide adduct of bisphenol A, trimethylolpropane acrylic acid benzoate, bisphenol A diglycidyl ether acrylic acid adduct, hydroxypivalic acid neopentyl glycol diacrylate, 2-acryloyl Examples include loxyethyl acid phosphate.

  Examples of the trifunctional acrylate (B2) include glycerin triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, triacrylate of trimethylolpropane ethylene oxide adduct, and the like.

  Examples of the 4- to 6-functional acrylate (B3) include pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and the like.

  Examples of the multifunctional (meth) acrylate monomer (B) that can be easily obtained from the market include, for example, Aronix M-210, M-240, M-305, M-402 (above, manufactured by Toagosei Co., Ltd.), light acrylate. PE-3A, DPE-6A (manufactured by Kyoeisha Chemical Co., Ltd.), Neomer DA-600 (manufactured by Sanyo Chemical Industries, Ltd.) and the like.

  Among these, as the polyfunctional (meth) acrylate monomer (B), preferred are trifunctional acrylate (B2) and 4-6 functional acrylate (B3), and most preferred is dipentaerythritol pentaacrylate from the viewpoint of curability. Dipentaerythritol hexaacrylate and combinations thereof.

Moreover, the polyfunctional (meth) acrylate monomer (B) in the present invention may contain a photosensitive acrylic oligomer (B4) in a part thereof. Examples of the photosensitive acrylic oligomer (B4) include urethane acrylate, polyester acrylate, and polyether acrylate having Mn of 1,000 or less and containing no carboxyl group and having two or more acryloyl groups in one molecule. Can be mentioned.
The content of the photosensitive acrylic oligomer (B4) in the polyfunctional (meth) acrylate monomer (B) is preferably 50% or less, more preferably 30% or less.

Based on the weight of the solid content of the photosensitive resin composition (Q) of the present invention, the content of the polyfunctional (meth) acrylate monomer (B) is 10 to 60% by weight, preferably 25 to 50% by weight. It is.
If it is 10% or more, the hardness of the cured product is further preferred, and if it is 60% or less, the developability is further improved.

Subsequently, the carboxyl group-modified cellulose (C) having an aromatic ring in the molecule of the present invention will be described in detail.
This (C) is a modified cellulose represented by the following general formula (1).

[R ^{1 to} R ³ in Formula (1) are each independently one or more of a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyalkyl group having 1 to 12 carbon atoms, an aromatic ring, and a carboxyl group. And an acyl group having 7 to 18 carbon atoms, and at least one of R ^{1 to} R ³ is an acyl group having 7 to 18 carbon atoms each having one or more aromatic rings and carboxyl groups. n is an integer of 7 to 10,000. ]

Examples of the modified cellulose include modified cellulose having a methoxy group, a hydroxypropoxy group and a carboxybenzoyl group, a modified cellulose having a methoxy group, a hydroxypropoxy group, an acetyl group and a carboxybenzoyl group, and the like.
For example, hydroxypropyl methylcellulose phthalate (HPMCP: manufactured by Shin-Etsu Chemical Co., Ltd.), hydroxypropyl methylcellulose acetate phthalate (HPMCAP: manufactured by Shin-Etsu Chemical Co., Ltd.) and the like can be mentioned.

The modified cellulose (C) preferably has a carboxyl group from the viewpoint of alkali developability. The carboxyl group content is represented by an acid value.
The acid value of the modified cellulose (C) is preferably 10 to 90 mgKOH / g. When it is 10 mgKOH / g or more, the developability is more easily exhibited, and when it is 90 mgKOH / g or less, the compatibility is further improved.

  The number average molecular weight (Mn) of the modified cellulose (C) is usually 1,000 to 1,000,000, preferably 3,000 to 100,000, from the viewpoints of photocuring reactivity and developability as the photosensitive resin composition. It is.

  Based on the weight of the solid content of the photosensitive resin composition (Q) of the present invention, the content of the modified cellulose (C) is preferably 3 to 25% by weight, particularly preferably 5 to 15% by weight. .

Finally, the photoradical polymerization initiator (D) in the photosensitive resin composition of the present invention will be described in detail.
Although it does not specifically limit as radical photopolymerization initiator (D), For example, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzophenone, methylbenzoyl Formate, isopropylthioxanthone, 4,4-bis (dimethylamino) benzophenone, 3,3-dimethyl-4-methoxy-benzophenone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, tert-butylanthraquinone, benzoin, benzoinmethyl Ether, benzoin ethyl ether, benzoin propyl ether, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-hydroxy 2-methylpropiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, 2-chlorothioxanthone, Diethylthioxanthone, isopropylthioxanthone, diisopropylthioxanthone, Michler's ketone, benzyl-2,4,6- (trihalomethyl) triazine, 2- (o-chlorophenyl) -4,5-diphenylimidazolyl dimer, 9-phenylacridine, 1, 7-bis (9-acridinyl) heptane, 1,5-bis (9-acridinyl) pentane, 1,3-bis (9-acridinyl) propane, dimethylbenzyl ketal, trimethylbenzoyldiphenylphosphine oxide, tribromomethylpheny Sulfone and benzyl-2-dimethylamino-1- (4-morpholinophenyl) - butan-1-one, and the like. (D) may be used alone or in combination of two or more.

  As the radical photopolymerization initiator (D), a commercially available product can be easily obtained. For example, Irgacure 907 is used as 2-methyl-1- (4- (methylthio) phenyl) -2-morpholino-1-propanone. Examples of 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one include Irgacure 369 (manufactured by Ciba Specialty Chemicals).

  The content of the photo radical polymerization initiator (D) based on the weight of the solid content of the photosensitive resin composition is preferably 0.01 to 5%, more preferably 0.05 to 3%, and particularly preferably 0.1. ~ 2%. If it is 0.01% or more, the sensitivity of the cured product can be exhibited more satisfactorily, and if it is 5% or less, the resolution can be further improved.

The photosensitive resin composition (Q) of the present invention may further contain other components (E) as necessary.
(E) includes inorganic fine particles (E1), sensitizers (E2), polymerization inhibitors (E3), pigments (E4), solvents (E5) and other additives (for example, leveling agents, silane coupling agents) , Adhesion imparting agents, viscosity modifiers, matting agents, dyes, fluorescent brighteners, yellowing inhibitors, antioxidants, antifoaming agents, deodorants, fragrances, bactericides, and fungicides) However, it is not limited to these.

As the inorganic fine particles (E1), metal oxide (E11) and metal salt (E12) can be used.
Examples of the metal oxide (E11) include known ones such as titanium oxide, silicon oxide, and aluminum oxide.
Examples of the metal salt (E12) include known ones such as calcium carbonate and barium sulfate.
Among these, from the viewpoint of productivity and cost, the metal salt (E12) is preferable, and calcium carbonate and barium sulfate, and particularly barium sulfate are more preferable.
The inorganic fine particles (E1) preferably have a volume average particle diameter of 1 to 5,000 nm, more preferably 10 to 30,000 nm, and particularly preferably 100 to 2,000 nm.
The volume average particle size can be measured, for example, using toluene as a solvent with a laser scattering particle size distribution analyzer LA-920 (manufactured by Horiba, Ltd.).

  The content of the metal oxide (E1) based on the weight of the solid content of the photosensitive resin composition is usually 0 to 50%, preferably 1 to 45%, particularly preferably 2 to 40%. If it is 50% or less, the flexibility can be further improved, and if it is 2 to 40%, the hardness of the cured product is particularly excellent.

  As the sensitizer (E2), nitro compounds (for example, anthraquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, benzanthrone, p, p'-tetramethyldiaminobenzophenone, carbonyl compounds such as chloranil, nitrobenzene, p -Dinitrobenzene and 2-nitrofluorene etc.), aromatic hydrocarbons (eg anthracene and chrysene etc.), sulfur compounds (eg diphenyl disulfide etc.) and nitrogen compounds (eg nitroaniline, 2-chloro-4-nitroaniline) , 5-nitro-2-aminotoluene, tetracyanoethylene and the like.

  The content of the sensitizer (E2) based on the weight of the radical photopolymerization initiator (D) is usually 0.1 to 100%, preferably 0.5 to 80%, particularly preferably 1 to 70%.

  There is no limitation in particular as a polymerization inhibitor (E3), What is used for normal reaction is used. Specifically, diphenylhydrazyl, tri-p-nitrophenylmethyl, N- (3-N-oxyanilino-1,3-dimethylbutylidene) aniline oxide, p-benzoquinone, p-tert-butylcatechol, nitrobenzene, Examples include picric acid, dithiobenzoyl disulfide, and copper (II) chloride.

  The content of the polymerization inhibitor (E3) based on the weight of the solid content of the photosensitive resin composition is preferably 0 to 1.0%, more preferably 0.01 to 0.5%, and particularly preferably 0.02. ~ 0.1%.

  As the pigment (E4), ordinary pigments can be used. For example, extender pigments: calcium carbonate, mica, kaolin, talc, aluminum silicate, barium sulfate, fine powder silica, clay, etc., coloring pigments; phthalocyanine blue, Examples thereof include phthalocyanine green, disazo yellow, anthraquinone yellow pigment, benzimidazolone, titanium oxide, carbon black, and the like, and these can be used alone or in combination. Among these, barium sulfate, talc, fine powder silica, and phthalocyanine green are preferable, and talc, fine powder silica, and phthalocyanine green are particularly preferable.

  The amount of the pigment (E4) used for the photosensitive resin composition is usually 0 to 50%, preferably 1 to 40% in the case of extender pigments. The coloring pigment is usually 0 to 5%, preferably 0.5 to 3%.

  As the solvent (E5), ordinary ones can be used. For example, organic solvents exemplified as the case of diluting the monomer during the production of the hydrophilic vinyl resin (A1) can be used, and these are used alone or in combination. be able to. Of these, ketones and esters are preferred.

  Among other additives, a normal leveling agent can be used, and for example, Modaflow manufactured by Monsanto Corporation can be used. A normal thing can be used as an antifoamer, for example, a silicone oil type antifoamer is mentioned.

  The photosensitive resin composition of the present invention can be obtained, for example, by mixing the above-described components with a known mixing device such as a planetary mixer.

  The photosensitive resin composition of the present invention is usually liquid at room temperature before curing, and its viscosity is 0.1 mPa · s to 10,000 mPa · s, preferably 1 mPa · s to 8,000 mPa at 25 ° C. -S. The viscosity can be measured with a BL type viscometer.

The photosensitive resin composition (Q) of the present invention can be suitably used as a photo solder resist such as a printed wiring board.
In order to use the photosensitive resin composition (Q) of the present invention as a photo solder resist, as a method of applying on the substrate, a method of applying with a screen printer, a roll coater, a curtain coater, etc., spray, brush, spatula, etc. The method of applying and the method of immersing are mentioned. The coating method is preferably a screen printing machine or a roll coater. As a film thickness, it is 0.5-500 micrometers normally, Preferably it is 5-100 micrometers.

After application, the composition is dried to remove volatile components contained in the composition. Examples of the drying method include a method of applying heat. As the heating device, a normal air circulation dryer, an electric furnace, a gas furnace, a far infrared furnace, or the like can be used. An electric furnace is preferred.
The drying temperature is usually preferably 60 ° C. to 90 ° C., and the drying time is usually preferably 30 seconds to 5 minutes.
The pressure during drying may be either reduced pressure or normal pressure, but reduced pressure is preferred.

Examples of the method for selectively exposing the obtained dried coating film include a method of irradiating actinic rays through a photomask having a pattern.
The actinic ray used for the exposure is not particularly limited as long as the photosensitive resin composition of the present invention can be cured. However, the low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultrahigh-pressure mercury lamp, xenon lamp, metal halogen There are lamps, electron beam irradiation apparatuses, X-ray irradiation apparatuses, lasers (argon laser, dye laser, nitrogen laser, helium cadmium laser, etc.). Of these, high pressure mercury lamps and ultrahigh pressure mercury lamps are preferred.
The amount of light irradiation in the exposure is appropriately selected depending on the amount of the polyfunctional (meth) acrylate monomer (B) and the radical photopolymerization initiator (D), but is preferably 20 to 300 mJ / cm ² .

By subjecting the resulting exposed coating film to alkali development, the unexposed portion is removed to form a coating film pattern. In the alkali development in the present invention, an alkaline aqueous solution is used as the developer. Examples of the alkaline aqueous solution include an aqueous solution of an inorganic salt such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and sodium bicarbonate; and an aqueous solution of an organic salt such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. Can be mentioned. These can be used alone or in combination of two or more kinds, and a surfactant such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant and a nonionic surfactant can be added and used.
Development methods include a dip method, a shower method, and a spray method, but the spray method is preferred. The temperature of the developer is preferably 25 to 40 ° C. The development time is appropriately determined according to the film thickness and the solubility of the resist. After development, it is usually washed with water and dried.

In order to ensure curing, post-heating may be performed as necessary after development.
The post-heating temperature is preferably 100 to 250 ° C, more preferably 150 to 240 ° C, and particularly preferably 180 to 230 ° C. The post-heating time is 5 minutes to 6 hours, preferably 15 minutes to 4 hours, particularly preferably 30 minutes to 3 hours. In order to suppress curing shrinkage in the coating film, it is also preferable to divide the heating temperature and the heating time into two stages or three stages.
The post-heating may be either reduced pressure or normal pressure, but reduced pressure is preferred.
Moreover, although it may carry out in air or in an inert gas, it is preferably in an inert gas.

  By the steps described above, a cured coating film having excellent alkali developability and extremely small warpage due to curing shrinkage is formed.

  Hereinafter, although an example and a comparative example explain the present invention further, the present invention is not limited to these. Hereinafter, unless otherwise specified, “%” represents “% by weight” and “parts” represents “parts by weight”.

<Production Example 1> [Production of hydrophilic resin (A-1)]
A glass Kolben equipped with a heating / cooling / stirring device, a reflux condenser, a dropping funnel and a nitrogen introduction pipe was charged with 56 parts isobornyl methacrylate, 36 parts 2-hydroxyethyl methacrylate, 8 parts methacrylic acid, and 250 parts cyclohexanone. And heated to 80 ° C. A solution in which 5 parts of azobisisobutyronitrile (V-60: Wako Pure Chemical Industries, Ltd., hereinafter referred to as AIBN) prepared in advance is dissolved in 50 parts of cyclohexanone after replacing the gas phase part in the system with nitrogen. 55 parts were dropped into Kolben at 80 ° C. over 10 minutes, and further reacted at the same temperature for 3 hours to obtain a hydrophilic resin (number average molecular weight (Mn): 8,800, SP value: 11.86, HLB value: 11). .98, acid value: 50 mgKOH / g), a cyclohexanone solution (A-1) was obtained (the solid content was 25%).

In addition, Mn is GPC measurement equipment (HLC-8120GPC, manufactured by Tosoh Corp.), column (TSKgel GMHXL 2 + TSKgel Multipore HXL-M, manufactured by Toso Corp.), polystyrene conversion measured by GPC method. Obtained as a value.
The SP value, HLB value, and acid value were determined as described above.
The same measurement method is used for the following production examples and comparative examples.

<Production Example 2> [Production of carboxyl group-modified cellulose (C-3)]
In a glass Kolben equipped with a heating / cooling / stirring device, a reflux condenser, and a nitrogen introduction tube, 98 parts of Metroze 60SH (manufactured by Shin-Etsu Chemical Co., Ltd.), 2.5 parts of trimellitic anhydride, and N, N- 900 parts of dimethylformamide was charged and dissolved uniformly. After dissolution, the gas phase portion in the system was replaced with nitrogen, and then heated to 80 ° C. 0.5 parts of triethylamine was added and reacted at the same temperature for 8 hours. After cooling, it was reprecipitated with diethyl ether and washed again with diethyl ether to obtain 85 parts of a white solid modified cellulose (C-3).

<Production Example 3> [Production of carboxyl group-modified cellulose (C-4)]
In Production Example 2, 84 parts of modified cellulose (C-4) were obtained in the same manner except that trimellitic anhydride was changed to 1.5 parts of pyromellitic anhydride.

[Preparation of photosensitive resin composition solution]
In an environment not exposed to ultraviolet rays, the above hydrophilic resin solution (A-1) and the following raw materials are charged in a glass container according to the formulation example in Table 1, and stirred until uniform, and a three-roll mill The photosensitive resin composition solution (Q ₀ -1) of Example 1 was prepared by kneading.

Hereinafter, similarly, the photosensitive resin composition solutions (Q ₀ -2) to (Q ₀ -4) of Examples 2 to 4 and the photosensitive resin composition solutions (Q ₀ '-1) of Comparative Examples 1 to 4 were used. ) To (Q ₀ ′ -4) were prepared. In addition, said thing was used about carboxyl group modified cellulose (C-3) and (C-4).

(B-1): “Neomer DA-600” (mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate: manufactured by Sanyo Chemical Industries, Ltd.)
(B-2): “KAYARAD DPCA-30” (polycaprolactone-modified dipentaerythritol hexaacrylate: manufactured by Nippon Kayaku Co., Ltd.)
(C-1): “HPMCP” (hydroxypropylmethylcellulose phthalate: manufactured by Shin-Etsu Chemical Co., Ltd.)
(C-2): “HPMCAP” (hydroxypropylmethylcellulose acetate phthalate: manufactured by Shin-Etsu Chemical Co., Ltd.)
(C′-1): “Shin-Etsu AQOAT” (hydroxypropylmethylcellulose acetate succinate: manufactured by Shin-Etsu Chemical Co., Ltd.)
(C′-2): “cellulose, microcrystal” (cellulose: manufactured by Wako Pure Chemical Industries, Ltd.)
(D-1): “Irgacure 907” (2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one: manufactured by Ciba Specialty Chemicals),
(E-1): “W-1” (Barium sulfate: Takehara Chemical Industries, Ltd.)
(E-2): “Anone” (cyclohexanone: manufactured by Sankyo Chemical Co., Ltd.)

The developability and warpage were evaluated by the following methods.
However, since (Q ₀ ′ -3) of Comparative Example 3 was not uniformly dissolved after stirring, evaluation of developability and warpage shown below could not be performed.

<Development evaluation method>
Each of the photosensitive resin composition solutions (Q ₀ -1) to (Q ₀ -4), (Q ₀ '-1), (Q ₀ ' -2), (Q ₀ '-4) is subjected to spin coating. It apply | coated to the copper plate so that the film thickness after drying might be set to 20 micrometers, and it was dried using the hot air circulation type dryer for 30 minutes at 80 degreeC.
Next, it exposed using the mask with a line | wire width of 20 micrometers with the irradiation amount of 200 mJ / cm < ² > using the ultraviolet-ray exposure apparatus (model | form: HMW-661-F-01 (made by Oak Manufacturing Co., Ltd.)). Thereafter, spray development was performed at room temperature using a 1% sodium carbonate aqueous solution at a pressure of 40 kPa for 20 seconds. Thereafter, the test pieces (Q ₁ -1) to (Q ₁ -4), (Q ₁ '-1), (Q ₁ ) are washed with ion-exchanged water at 30 ° C at the same time as the development time at a pressure of 60 kPa. '-2) and (Q ₁ ' -4) were created. The following criteria for each test piece have been revised in the same way as below. >.
○: No residue visually.
Δ: There is a little residue visually.
X: There are many residues visually, and pattern formation is insufficient.

<Evaluation method of warpage>
The above photosensitive resin composition is applied to a glass epoxy FR-4 substrate (JIS C6480: GE4F standard compliant product described in “General Rules for Copper-clad Laminates for Printed Wiring Boards”) having a substrate thickness of 60 μm and a copper foil thickness of 12 μm. Film thickness after drying by spin coating method for each of solutions (Q ₀ -1) to (Q ₀ -4), (Q ₀ '-1), (Q ₀ ' -2), and (Q ₀ '-4) Was applied to a copper plate so as to be 30 μm, and dried at 80 ° C. for 60 minutes using a hot air circulating dryer. The entire surface is exposed at an irradiation dose of 500 mJ / cm ² by the ultraviolet exposure apparatus described above, developed by the method described above, and then thermally cured to form test pieces (Q ₂ -1) to (Q ₂ -4), (Q ₂ ′). -1), (Q ₂ '-2), and (Q ₂ ' -4).
The test piece (400 mm × 300 mm) was used as a test piece, the height from the four corner planes of the test piece on the plane was measured, and the sum of the values was determined as the amount of warp deformation, and determined according to the following criteria.
○: 20 mm or less Δ: 20 mm to 40 mm
×: 40 mm or more

  The evaluation results of developability and warpage are shown in Table 1.

  As is clear from Table 1, the alkali-developable photosensitive resin composition shown in the examples of the present invention can provide a cured coating film having excellent alkali developability and extremely low warpage due to curing shrinkage. it can.

The alkali-developable photosensitive resin composition of the present invention is excellent in alkali developability and has very little warpage due to curing shrinkage. Therefore, a solder resist for manufacturing a printed wiring board, a photoresist for a liquid crystal display substrate, and an etching for a printed wiring board It can be used as a resist or a plating resist for printed wiring boards.

Claims (5)

Hydrophilic vinyl resin (A1) or hydrophilic epoxy resin (A2) , polyfunctional (meth) acrylate monomer (B), carboxyl group-modified cellulose (C) having an aromatic ring in the molecule, and initiation of radical photopolymerization An alkali-developable photosensitive resin composition (Q) containing an agent (D), wherein the content of the modified cellulose (C) is based on the weight of the solid content of the photosensitive resin composition (Q). The photosensitive resin composition which is 3-25 weight% and the acid value of this modified cellulose (C) is 10-90 mgKOH / g.   The photosensitive resin composition according to claim 1, wherein the hydrophilic resin (A) has an HLB value of 4 to 19.   The photosensitive resin composition of Claim 1 or 2 whose solubility parameter (SP value) of this hydrophilic resin (A) is 7-14. Based on the weight of the solid content of the photosensitive resin composition (Q), the content of the hydrophilic resin (A) is 10 to 80% by weight, and the content of the polyfunctional (meth) acrylate monomer (B) The photosensitive resin composition according to any one of claims 1 to 3 , wherein is 10 to 60% by weight. Claim 1-4 The photosensitive resin composition according to any one of a photo solder resist used for a printed wiring board.